Bending die



Aug. 26, .1941. R. F. MCMAHAN BENDING DIE Patented Aug. 26, 1941 BENDmG DIE Roy F. McMillian, Louisville, xy.

original application March ze, 1936,` serial No. 70,933, now Patent No. 2,201,193, dated May 21,

1940. Serial N0. 333,073

2 Claims.

This invention relates to improvements in bending dies, and is a division of my earlier application, Serial Number 70,933, filed March 26, 1936, and entitled Hanger and method of attaching same, now Patent 2,201,193, May 21,

In the aforesaid application, there is disclosed a hanger formed from sheet metal and the method of securing the same to a wooden bar. The hanger has incorporated therewith a pair of re1- atively spaced arms, between which a wooden bar is positioned with lits side portions in abutting relation with corresponding portions of the spaced arms. The arms have a length greater than the thickness of the wooden bar, and the extremities of the arms are bent in a novel manner so as to provide a, new method of securing a metal member to a Wooden bar. This method comprises bending the unsupported portions of the arms, inwardly and downwardly over a surface of the bar and at the plane of the said surface; then simultaneously bending the extremity of each of the said arms downwardly and inwardly with respect to its arm and into approximately arch-shape while the extremity is spaced from the said surface; continuing both of said bending movements until the free edges of the said extremities contact with and are forced into the said surface during the aforesaid arch-forming operation; and retaining the abutting relation of the arms with the said bar during the aforesaid bending operations.

Therefore, it is the object of this invention to provide a simple and effective bending die for performing the steps of the aforesaid method in a simple and economical manner.

Accordingly, it is a. further objectl of this invention to provide a bending die having a construction suitable for practicing theV salient characteristics of the method on articles other than the hanger illustrated in my aforesaid application.

These and other objects wlill be apparent to those skilled in the art as the following description is read in connection with the accompanying drawing, in which:

Figure 1 is a vertical sectional-view of the die block illustrating substantially the .first step of bending the arms inwardly and downwardly over the surface of the Wooden bar I2;

Figure 2 is a similar vertical sectional-View illustrating the forming tool I6 advanced in its downward movement relative to the stationary Divided and this application May 3, 1940,

-ning of the second step of bending the arms into approximately arch-shape is illustrated;

Figure 3 is likewise a vertical sectional-view illustrating the forming tool I6 further advanced in the arch-forming operation;

Figure 4 is also a vertical sectional-view and illustrates the forming tool I6 still further advanced in the arch-forming operation;

Figure 5 Ais likewise a, vertical sectional-view illustrating the forming tool I6 substantially beginning -its operation of forcing the extremities I'I into the wooden bar I2;

Figure 6 is a similar vertical sectional-view and illustrates the forming tool I6 substantially completing the operation of forcing the extremities I1 into the wooden bar I2;

Figure '7 is a partial plan view of the completed article, on. a slightly reduced scale, as viewed from the outer face of the metal member I4; and

Figure 8 is a vertical sectional-view illustrating the relation of the arms I5 of the metal member I4 relative to the wooden bar I2 prior to operation thereon by the forming tool I6.

In the foregoing drawing only vertical sectional-views of the bending die were presented, and it is to be understood that the cross-sectional contours thereof are substantially the same throughout the length of the die. It is to be further understood that the forming tool I6 is provided with a suitable mounting means, so that the same may be operatively connected to any actuating mechanism for imparting a vertical sliding movement thereto. Similarly, it is to be understood that the anvil I9I, or stationary portion of the die, is secured to a stationary table in operative relation with the forming tool I6.

The specific bending die illustrated in the drawing, is primarily employed for securing a sheet-metal bracket to a wooden bar, which bar may be a chair rung, table leg or similar hardware used in the manufacture of furniture. Therefore, it is to be understood that the contour of the anvil ISI, the depending arms IBI, and the plane of the forming contours I8 may be altered to accommodate the particular shape of the metal and wooden members. In this respect, it will be apparent that the teachings of this invention may be utilized in attaching a single arm I5 to a wooden bar I2, or the wooden bar may comprise several pieces placed between the arms I5. Accordingly, it is important to observe the relation existing between the inner faces of the depending arms ISI relative to the anvil I9I. In Figure 2 substantially the begin- 55 outer faces of the arms I5; the relation existing between each extremity I'I and its corresponding forming contour I8, and the relation existing between each projection I9 and its corresponding extremity I1, when the same is forced into the wooden bar I2, as illustrated in Figure 5. For these specific relations reference is directed to the drawing.

Thus, in' specifically describing the particular forming tool illustrated in the accompanying drawing, I do not desire tobe limited other than by the scope of the appended claims. Therefore, although the means for retaining the arms Il in abutting relationship with the corresponding sides of the wooden bar I5 comprises arms IBI secured tothe forming tool I6 in the preferred embodiment of my invention, such arms may be dispensed with, and, the metal member placed into a. channel formed in the anvil I9I, or separate clamping members may be forced into engagement with the arms I5 by action of the forming tool I6.

However, in practicing the method disclosed in my co-pending application Serial No. 70,933, it was observed that it is desirable, for most applications, to provide the movable formingtool I6 with depending guide-arms I6I. From the foregoing, it will be apparent that the bending die of the illustrated embodiment is adapted to secure a metal member to a wooden bar, wherein the metal member has a portion thereof formed into substantially a channel shape having legs or arms I5 longer than the thickness of the wooden bar, as illustrated in Figure 8, and, as illustrated in Figure 7, the arms I5 extend longitudinally along the corresponding sides of the Wooden bar.

In Figure 6 the forming tool I6 is shown in its closed position relative to the anvil ISI, and the final condition of the arms I5 relative to the wooden bar I2 is clearly illustrated.

The bending die of the present invention is not to be confused with the usual tool employed to fold a metal arm laterally against the side face of a bar, or in which the free end of an arm is clinched into a wooden bar, as the contour I8 of the present invention is constructed and arranged to bend the arm into arch shape while the extremity I'I is spaced from the outer surface of the bar I2, as progressively illustrated in Figures 3, 4 and 5, and then forcing the extremity I'I into the bar I2 during the archforming operation, as illustrated in Figure 6. Thus, it will be apparent that, between the stages illustrated in Figures 5 and 6, the extremity I'I moves in an arcuate path, that is, the unsupported end I5a slides longitudinally along the arched contour I8 until the extremity I1 is pushed into the bar and beneath the outer surface thereof. During these final stages, the corresponding projection I9 penetrates the out'er surface of the bar and assures a thorough local spaanse [fl-forcibly the arms I6, and to retain the same assure proper engagement of the arms Il under reasonable manufacturing variation.

Forming contours I8, of substantially semicircular shape, are provided within the forming tool adjacent each corresponding depending arm III, and these contours I8 extend longitudinally along the forming tool, for a distance sufficient compression of the bar beneath the arched arm.

Therefore, the salient feature of the bending die is the arched contour I8 and its relation to the extremity Il, and the relative depression of the face I9a so as to provide a projection I 9 for penetrating the outer surface of the wooden bar to provide the final securing operation.

Thus, to secure a metal member Il having a pair of oppositely disposed arms I5, .as illustrated in Figure 8, the bending die comprises an anvil I9I upon which the metal member Il is placed, as indicated in Figure 1. The bending die also comprises a forming tool I6 having a pair of depending arms I6I adapted to engage to accommodate the arms I5 of the metal member I The inner face I9a of the forming tool is depressed to form projections I9, and these projections merge into the corresponding forming contours I8 substantially diametrically opposite the point of tangency of the' inner face of the corresponding depending arm I6I, and have their ends pointed for penetrating the wooden bar substantially adjacent the arched portion of the corresponding arm I5. The projections I9, like the forming contours I8, yextend longitudinally along the forming tool, so as to accommodate the arms I5 of the metal member I4.

In operation, the metal member I 4 containing the bar I2 is placed upon the anvil ISI, and it is to be understood that the anvil I9I is provided with guides for locating the arms I5 of the member I4 relative to the forming tool I6.

-The forming tool is then moved downwardly, and the inner faces of the depending arms I6 I forcibly engage the arms I5 for retaining the same in abutting relationship with the corresponding sides of the bar I2.

As the forming tool advances downwardly, the extremities vI'I engage and slide laterally over the arched surfaces of the corresponding forming contours I8, and the unsupported ends I5a oi the arms I5 bend inwardly and about the top corners of the bar, as illustrated in Figure 1. This bending operation continues until the extremities arrive at points substantially beyond corresponding mid points of the arches, whereupon each of the ends I5a begin to assume an arch shape, as illustrated in Figure 2.

During the arching operation, the extremities continue to slide laterally over the arched surfaces of their corresponding forming contours I8, by reason of the relative stiffness of the metal. This action is illustrated in Figures 2, 3 and 4.

'Ihe final stage of the arching operation is completed while each extremity is spaced from the outer surface `of the bar, and preferably slightly before the extremities contact the said outer surface, as evidenced by Figures 4 and 5.

Each end I5a at this stage is substantially in face contacting relation with its corresponding forming contour I8, and, as the downward movement of the forming tool I6 continues, each end I5a slides over the surface of the corresponding forming contours I8 in substantially face contacting relationship, whereupon the -extremities II are brought into contact with and forced into the outer surface of the bar I2, as illustrated in Figures 5 and 6. Thus, in forcing the extremities into the bar I2, such operation is accomplished by sliding each end I5a laterally over the surface of its corresponding forming contour I8. l

'I'his securing operation provides a minimum rupture for the fibres of the wood beneath the arched ends I5a. y

Thus, careful analysis of Figures 5 and 6, in

view of the foregoing, will reveal that the projections I9 penetrate the bar I2 adjacent their corresponding arched end lia and support the same until the securing operation is completed, as illustrated in Figure 6. Whereupon the forming tool I6 is withdrawn and the assembled article removed from the anvil ISI.

While I have shown and described what I considered to be the most practical embodiment of my invention, it is to be understood that various changes in construction may be made under the scope of the appended claims.

Having thus described my invention, I claim:

1. In apparatus for securing the legs of a sheet metal channelto a rectangular wooden bar disposed within the trough of the channel, having its side and bottom faces, respectively, engaging the inner faces of the legs 'and base of the channel, and having its top face substantially below the free end edges of the legs, the combination of upper and lower relatively movable pressure applying members; opposed longitudinal dies on the v said pressure applying members; one of said dies having a longitudinal opening of substantially the same width as that of the sheet-metal channel with substantially vertical side walls for slidably engaging the outer faces of the legs of the channel, the said one die having two semi-circular concave-surfaces formed therein at the base of the said opening, the outer edge of each semicircular surface each respectively being tangent with the corresponding vertical wail of the opening and extending longitudinally therealong, the said one die also having its medial portion between the respective concave-surfaces cut below the inner edges of each respective concave surface; the other of said die members having a longitudinal portion substantially equal in width to that of the opening, the said other die member also having a fiat surface for engaging the base of the sheet-metal channel, and vertical sidewalls for slidably engaging the vertical walls of the said opening; the vertical side walls of the said opening each respectively engaging the outer faces of the legs of the channel during the relative movement of the said dies for retaining -the inner faces of the legs in abutting relation with the respective side faces of the bar, and guiding the free end edges of the legs into engagement with each respective concave surface to provide a lateral bending of the extremity of each leg inwardly and downwardly over the top face of the wooden bar and at the plane thereof, and upon further relative movement of the said dies to bend simultaneously the extremity of each leg downwardly and inwardly with respect to the legs of the channel into approximately arch-shape while each extremity is spaced from the top face of the bar, and upon a still further relative movement of the said dies to continue both of the bending movements until the free end-edges of the legs contact with and are forced into the top face of the wooden bar during the arch forming operation.

2. In apparatus for retaining. the legs of a sheet-metal channel in abutting relationship with a wooden member while bending the extremities into approximately arch shape and continuing said bending until the free end-edges of legs contact with and are forced into a surface of the bar, the combination of upper and lower relatively movable pressure applying members; opposed longitudinal dies on'the said pressure applying members; one of said dies having a longitudinal opening of substantially the same width as that of the sheet-metal channel, and having substantially vertical side walls for slidably engaging the outer faces of the legs of the channel, the said one die also having two semi-circular concave-surfaces formed therein at the base of the said opening, the outer edge of each semi-circular surface each respectively being tangent with a vertical wall 0f the opening and extending longitudinally therealong, the said one die also having its medial portion between the concave surfaces cut below the inner edges of each respective concave surface; and the other of said die members having a longitudinal portion substantially equal in width to that of the opening, and also having a face for engaging the base of thechannel, and likewise vertical sidewalls for slidably engaging the vertical walls of the opening.

` ROY F. MCMAHAN. 

